You can uninstall or removes an installed maradns-zoneserver package itself from Ubuntu 14.04 LTS (Trusty Tahr) through the terminal,
$ sudo apt-get remove maradns-zoneserver
If you would like to remove maradns-zoneserver and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove maradns-zoneserver
If you use with purge options to maradns-zoneserver package all the configuration and dependent packages will be removed.
$ sudo apt-get purge maradns-zoneserver
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove maradns-zoneserver